This application claims priority to United Kingdom patent application number 0009793.1 filed on Apr. 25, 2000.
The present invention relates to lock mechanisms and in particular lockable latch mechanisms for use with motor vehicles.
Known vehicle door latch mechanisms include a locking feature, whereby the latch can be locked, thereby preventing opening of an associated door from the outside (but allowing opening of the door from the inside) or the latch can be unlocked, thereby allowing opening of the associated door from the both inside or the outside.
Known latch mechanisms also incorporate superlocking (also known as deadlocking) features whereby in the event that an unauthorized person gains access to the inside of a vehicle, that person is nevertheless prevented from opening the door from the inside.
Previously, motor driven central locking systems have been operated by providing a pulse of energy to a motor which rotates a locking gear between an unlocked and locked position. The locking gear is prevented from turning to the superlocked position by a solenoid actuated pin arrangement in a track or recess cut from the lock gear. In order to superlock the door, a superlock command is passed to the lock system and the solenoid withdraws the pin from the track. A pulse of energy is then applied to the motor to drive the locking gear. As the locking gear is not restricted in its travel by the pin, it can move to a superlock state. However, such an arrangement requires two actuators namely the drive motor and the solenoid and further requires and appropriate control arrangement to ensure synchronization between the motor and solenoid.
It is an object of the present invention to provide an improved vehicle lock mechanism.
Thus according to the present invention there is provided a lock mechanism including a lock lever movable between unlocked, locked and superlocked positions, the lock lever being connected to further components of the lock mechanism to provide for corresponding unlocked, locked and superlocked conditions of the lock mechanism, the lock lever being operably movable between the unlocked, locked and superlocked positions by a stepper motor.
In that way, one drive effects stepped motion between the three lock lever positions without the need for a solenoid actuation pin.